1). Field of the Invention
This invention relates to a system and method for transferring electric power.
2). Discussion of Related Art
A multitude of devices these days use rechargeable batteries, for example lithium-based rechargeable batteries. Mobile phones, vehicles, drones and the like are normally disconnected from an electric power supply grid when they are being operated, which causes their batteries to lose their charge. The batteries then have to be connected to an electric power supply grid so that they can be recharged.
It usually takes at least a half an hour, and often more time to fully recharge a fully-depleted battery. Batteries generate a fair amount of heat when they are being recharged and an excessive amount of heat can cause damage to a battery, which can destroy the battery or reduce its life expectancy. Battery chargers are designed to limit the rate at which power is provided to the batteries when they are being recharged so that their temperatures remain below the temperature at which damage may occur.
A battery charger normally includes a single phase alternating current power supply conductor with a socket that is connected to a wall outlet. The wall outlet is connected to an electric power supply grid. The battery charger includes a rectifier that converts alternating current received from the electric power supply grid to direct current. The direct current is then provided through a delivery circuit to positive and negative terminals on a battery. A power controller may be included to control the amount of power that is provided to the battery, although it may be possible to control power provided to the battery by connecting multiple batteries in series or in parallel.
When designing a battery charger, various factors are normally taken into account. For example, the voltage and power supplied by the electric power supply grid, the inclusion of transformers and the number and sizes of the batteries are taken into consideration, especially for purposes of minimizing the temperatures of the batteries while they are being charged. However, no satisfactory explanation has been forthcoming as to why the batteries heat up in the first place. For example, Ohm's law, which states that the sum of voltages in a closed loop will always equal zero, does not provide a satisfactory explanation as to why the batteries heat up during recharge.
Heat generation results in a high temperature that limits how fast a battery can be charged. A high temperature also limits the voltage to which a battery can be charged, which means that the capacity of the battery is decreased with a corresponding decrease in time before the battery runs out of charge. High charging temperatures means that the life time of the battery, i.e. the number of times that the battery can be recharged, is reduced as described in “BU-806a: How Heat and Loading affects Battery Life.” A high temperature also results in a danger of explosion as described in “Why phones explode sometimes, and what you can do to protect yourself” by Robert Triggs. It is also not possible to recharge batteries that are considered not rechargeable. For example, lithium-based batteries are rechargeable, but that alkaline-based batteries are not rechargeable. A net negative effect on the environment is created when alkaline-based batteries are dispensed as described in “What Do Batteries Do to the Environment If Not Properly Recycled?” by Kathy Kattenburg.
Outside of the field of battery chargers, other electric power delivery systems often suffer the same fate of excess heat that cannot be readily explained. For example, it is not always possible to explain why certain electric fires happen when the systems are subsequently analyzed for failures using engineering principles that are commonly available at this time.